The invention relates to a device for producing work pieces perforated by means of electron beams, in particular foil-blanks, as for shoe upper-parts, with an electron beam working chamber, which can be evacuated, situated outside the work chamber input and output appliances for the input of unperforated work pieces or the output of perforated work pieces, and a transport appliance with a transport track stretching between the input and output appliances and the work chamber over air locks for controlled transport of work-piece carriers, to which the workpieces are applied in predetermined positions.
It is well known that it is possible to give workpieces, especially synthetic foils, a required perviousness with respect to gases in a specially advantageous way by perforation with electron beams or other energy beams; in this way, very fine and if required even practically invisible perforation bores can be produced very quickly and with a large surface density, whereby these perforation bores, even with work-pieces made of synthetic materials show only a slight tendency to close again under the influence of plastic deformation, because the walls of the perforation bores are set in a crust-like formation as a result of the thermic effect of the electron beam. It has already been suggested in the production of foil blanks not to carry out such perforation work on continuous foil tracks but on individual blanks, especially for shoe upper parts; this offers, among other things, the advantage, that possible impression and moulding operations taking place under the influence of heat on the individual blanks can be carried out before perforation, so that the danger that the perforation bores are closed again by subsequent work processes under the influence of heat is excluded. It has also been suggested that such blanks should be guided either continuously or by means of continuously working transport appliances into the working area of the electron beam perforation machine, that is, in its work chamber. It has however up to the present time not been possible to put perforation machines of the suggested type into practice. This can presumably be traced back to the fact that the attainable production quantities and production speeds were not sufficient in comparison with the very high expenditure necessary for the electron beam generator.